DC casting mold assembly

ABSTRACT

A readily changeable DC mold assembly comprising a tubular flanged mold, a coolant jacket and preferably a quick-release connecting means to urge the mold flange into engagement with the water jacket. A resilient, rubber-like gasket material is disposed between the portions of the water jacket and the mold flange to create a water-tight seal therebetween. A spacer means is disposed between the baffle member and the tubular portion of the mold to positively position the mold body.

United States Patent [1 1 Foye DC CASTING MOLD ASSEMBLY [75] Inventor:John J. Foye, Livermore, Calif.

[73] Assignee: Kaiser Aluminum & Chemical Corporation, Oakland, Calif.

22 Filed: June 1,1973

[21] Appl.No.:365,835

Related U.S. Application Data [63] Continuation-impart of Ser. No.262,510, June I4.

1972, abandoned.

[52] U.S. Cl. 164/283 [5|] Int. Cl 322d 11/12 [58] Field of Searchl64/82, 283

{56] References Cited UNITED STATES PATENTS 2,862,265 12/1958 Vaughn etal. 164/283 M 3,059,295 l0/l962 Vosskuehler 164/283 M 3,749.52 7/l973Dore et al l64/283 FOREIGN PATENTS OR APPLICATIONS 1,054,090 l0/l953France l64/283 M [ll] 3,885,617 5451 May 27, 1975 867,]48 2/1953 Germany164/283 M 8l3.755 9/l95l Germany v. 164/283 M 835,790 4/1952 GermanyPrimary ExaminerFrancis S. Husar Assistant Examiner-V. K. RisingAttorney, Agent. or Firm-Paul E. Calrow; Edward J Lynch [57] ABSTRACT Areadily changeable DC mold assembly comprising a tubular flanged mold, acoolant jacket and preferably a quick-release connecting means to urgethe mold flange into engagement with the water jacket. A resilient,rubber-like gasket material is disposed between the portions of thewater jacket and the mold flange to create a water-tight sealtherebetween. A spacer means is disposed between the baffle member andthe tubular portion of the mold to positively position the mold body.

13 Claims, 7 Drawing Figures SHEET FII3 .EI

FATE N TEU 2 1915' SHEET .HIH lrli. k J M Illl 5 DC CASTING MOLDASSEMBLY RELATED APPLICATIONS This application is a continuation-in-partof patent application Ser. No. 262,5 l0, filed June 14. I972 nowabandoned.

BACKGROUND OF THE INVENTION The invention relates to the continuous orsemicontinuous DC (direct chill) casting of metal, particularly lightmetals, such as aluminum. The DC casting of light metals is a well-knownprocess and has been commercially practiced for many years. Initially,the molds were of simple design and comprised an open-ended tubular moldbody provided with a flange portion extending out radially from the feedend of the mold from which the mold was supported. During the castingoperation, the exterior of the mold body and the emerging ingot wereflooded with coolant from sprays positioned concentrically with themold. The cooling water, which is usually recycled in DC castingoperations, carries considerable quantities of sediment which canpartially or completely block coolant sprays. On those areas of the moldbody where coolant flow is reduced due to spray blockage, the resultanttemperature increase of the mold wall thins out the lubricant whichdetrimentally affects the surfaces of the cast ingot. If the coolantflow is severely reduced or stopped over a particular area of the moldbody, the molten metal in the mold can melt completely through the moldbody and flow into the casting pit. The surface quality of the ingotsformed with the simple molds was very often poor because of the unequaldistribution of coolant around the periphery of the mold and theemerging ingot. Moreover, the operational life of the tubular flangedmolds was relatively short. Water jacketed mold assemblies weresubsequently developed to eliminate the possibility of melting the moldand also provide for a more dimensionally stable mold during casting.However, due to the low velocity of water adjacent the water-jacketedmold surfaces, the heat transfer rates between the mold and liquid waslow. The low velocity water also allowed the formation of scale on theouter surfaces of the mold, and frequently, the formation of gas on thesurfaces which further impedes heat transfer. To provide more uniformand higher heat transfer rates, baffles were positioned concentricallywith the tubular moid body to increase the water velocity adjacent themold surfaces and to thereby minimize scale buildup and gas filmformation. The baffle was usually made integral with either the waterjacket or mold requiring extensive, complicated machining andconsiderably increasing the cost of the mold assembly. Thewater-jacketed molds were characterized by a much longer operationallife because the assemblies were more rugged and less susceptible tothermal distortions. However, changing a mold with a water jacket due tonormal wear or to change mold size (either length or diameter) was avery difficult and timeconsuming task because the entire mold assemblyhad to be removed including the water jacket. This required thedisconnecting of water lines. lubrication lines, and the like. Withhorizontal continuous DC casting, mold changes are relativelyinfrequent, and thus the downtime for mold changes is not signifcantcompared with casting time. in the case of semicontinuous vertical DCcasting, molds are frequently changed, and the downtime for mold changesis very high compared with casting time. With the advent of level-fedreservoir top molds, sometimes referred to as heat insulated molds orhot top molds, described and claimed in US. Pat. No. 3,494,410, whereinthe molten metal level in the reservoir above the chill mold ismaintained at approximately the same level as in the feeding trough,mold changing became a more difficult and time-consuming task.

The water jacket and mold body members of the prior art mold assemblieswere characteristically joined through screwor bolt-type connectors. Dueto the relatively great forces generated by these connectors to effect awater-tight seal between the members, the mold body frequently becamedeformed requiring early replacement of the mold.

The mold bodies for jacketed mold assemblies generally were quiteexpensive due to the machining required for various lubrication andcooling conduits which were usually included in the mold body.

Against this background, the present invention was developed.

SUMMARY The present invention provides an improved DC mold assembly,particularly useful in the DC casting of light metals, such as aluminum.The mold body of the assembly of the present invention can be quicklyreplaced when necessary due to normal wear or due to the desire tochange mold diameter or mold length and allows the interior surfaces ofthe mold assembly to be quickly exposed for removal of buildup on themold surfaces or blockage of coolant passageways. The mold assembly ofthe present invention comprises a readily changeable, open-ended tubularmold body provided with an upper or flange portion which extends outradially from the feed end of the mold. The flange portion of the moldbody is supported on the vertically extending leg of a coolant jacketwhich is positioned concentrically with the mold body and forms acoolant chamber therewith. The horizontally disposed leg of the coolantjacket supports a vertically extending baffle member which is concentricto the mold body and spaced therefrom. At least one spacing member isprovided between the baffle member and the mold body to maintain apredetermined spatial relationship therebetween and to positivelyposition the mold body. A resilient, rubber-like gasket material isprovided between the mold flange and the vertically extending leg of thewater jacket. A readily disengageable and engageable connecting meansurge the flange portion of the mold into a soft, water-tight sealingengagement with the water jacket leg. The spacing member provides thenecessary positive positioning of the mold body. To replace the moldbody, the connecting means are disengaged, the mold body is removed,and, if mold length or diameter is to be changed, the baffle member isalso removed. The new baffle member and a new mold body are positioned,and the connecting means re-engaged. Because the water jacket remains inposition and is relatively permanent, it is unnecessary to remove thecoolant and lubricant lines connected thereto. The mold of the presentmold assembly is of relatively simple design which does not require theextensive and complicated machining required by the prior artwaterjacketed molds.

DESCRIPTION OF THE DRAWINGS FIG. I is a side view partially sectionedofa mold assembly of the present invention.

FIGS. 2 and 3 are cross-sectional views of embodiments of the presentinvention in which the mold body dimensions are smaller than that shownin FIG. 1.

FIG. 4 is an exploded side view partially sectioned view of the moldassembly shown in FIG. I and illustrates the method of assembly.

FIG. 5 is a perspective view of another embodiment of the presentinvention.

FIG. 6 is a cross-sectional view of another embodiment of the presentinvention.

FIG. 7 is a cross-sectional view of the embodiment shown in FIG. Iwherein the spacing member is formed integral with the mold and isseated in a recess provided in the baffle member.

In the drawings, all corresponding parts are numbered the same.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. I, thecasting mold assembly of the present invention comprises an open-endedtubular mold body 10 provided with a flange portion 11, the innersurfaces of the mold body I0 defining the mold bore 12. The mold isformed of a highly heatconductive material, such as aluminum or copper,A generally L-shaped coolant jacket 13 defines a coolant chamber I4 withsaid mold and is adapted to maintain a body of coolant in contact withthe outer surfaces of the mold body 10. The vertically extending leg 15of the coolant jacket supports the mold through flange portion 11.Preferably, the horizontally extending leg 16 of the waterjacket isprovided with a shoulder or re cess 17 adapted to seat and support aseparate, vertically extending baffle member 18 which is positionedconcentrically with the mold body 10, and in this case, the shoulder 17and the contacting surfaces of the baffle member 18 should be machinedto close tolerances to prevent or minimize coolant leakage. If no moldsize changes are contemplated, the baffle member 18 can be made integralwith the leg 16 of the water jacket. The coolant jacket 13 is rigidlyfixed in a suitable man ner to a support base, such as a table top (notshown). At least one spacer means 19 is situated between the mold body10 and the baffle member 18 to positively position the mold body I0 andto maintain the spatial relationship of the mold body 10 with respect tothe baffle member 18 to thereby maintain the coolant velocity in theconduit 20 defined by these two members within desired limits tomaintain proper uniform heat transfer rates. Preferably, the spacermeans is formed integral with the baffle member 18 and machined to closetolerance for interflt with the recess 21 provided on the outer surfacesof mold body 10 as shown in the drawing. However, the spacer means maybe a separate member or formed integral with mold body It] as shown inFIG. 7. Preferably, the spacer means 19 is a projecting ridge on thebaffle member 18 and is provided with a plurality of coolant passageways22 which direct coolant to impinge on the surface of the emerging ingot.

The upper face of the vertically extending leg 15 of the water jacket 13is provided with a groove 31 adapted to receive a resilient, rubber-likeO-ring 32. Preferably, the material of O-ring 31 is a natural rubher,elastomer or equivalent material having a hardness of about 25-80,preferably about 3060 as measured with a Shore Durometer to effect asoft, water-tight seal between the mold flange 11 and the water jacketleg I5. Clamping means 33 urge the mold flange II into a water-tight,soft sealing engagement with the upper surface 30 of the water jacketleg I5. Preferably, the clamping means 33 are of a quick-release typeand effects a clamping force of less than about 500 pounds between themold flange and water jacket leg. A suitable connector is Model No. 2Link-Lock sold by the Simmons Fastener Corporation, Albany, NY. As shownin the Figure, one element 34 of the clamping means 33 is fixedlyattached to clamping ring 35 which is utilized to urge the mold flangeinto a soft-sealing engagement with the water jacket. However, ifdesired, one element 34 ofthe connecting means may be affixed to theupper surface of the mold flange 35. Coolant, usually water, isintroduced into coolant chamber I4 through conduit 27.

A lubricant passageway 40 passes through the upper leg 15 of the waterjacket. Passageway 40 is coaxial with lubricant conduit 41 located inthe mold flange and is in fluid communication therewith to thereby passlubricant to the groove 42 provided in the upper surfaces of the moldflange II. Lubricant is introduced into passageway 40 usually underpressure from conduit 45. A lubricant seal 46 minimizes lubricantleakage between the flange and coolantjacket leg 15, Positioning means,such as locating pin 50 and cavity 51, which is adapted to receive thelocating pin, position the mold body with respect to the water jacket.This assures alignment of the lubricant passageways 40 and 41.

In the embodiment shown in FIG. 2, the water jacket 13 is essentiallythe water jacket shown in FIG I, but the mold body 10 has a smallerdiameter than that shown in FIG. 1. The baffle member I8 has beenreplaced to compensate for the smaller diameter mold bore. In FIG. 3,the mold length is shortened in comparison with the mold length shown inFIG. I. The baffle member 18 has also been changed to compensate for thedifferent size mold. The baffle member 18 usually must be changed eachtime the mold diameter or mold length is changed to maintain thevelocity of coolant in the conduit 20 at the desired levels, and toprovide a properly positioned point of impingement for the coolantstreams.

FIG. 4 is an exploded perspective view of the mold assembly andgenerally illustrates the method in which the mold is installed ordisassembled. The coolant jacket 13, which is usually rigidly fixed to asupport base (not shown), is relatively permanent. To disassemble theassembly, the connecting means 33 are disengaged and the mold l0 and, ifa different size mold is to be inserted, also the baffle member 18, arelifted out of the assembly. To reassemble, the new baffle member 18, ifany, and a new mold I0 are merely placed into position and theconnecting means reengaged Whereas the prior art jacketed molds requiredup to an hour or more for replacement by skilled personnel, such asmillwrights, pipefitters and the like, the mold assembly of the presentinvention can be replaced in a matter of about a minute by castingstation operators. Moreover, the mold assembly of the present inventionallows for the rapid exposure of the interior portions of the moldassembly for removal of surface buildup and obstructions.

FIG. 5 is a perspective view of a level-fed reservoir top mold. The feedtrough is generally shown at 60 with trough extension 61 which allowsmolten metal to flow into the reservoir top generally indicated at 62.The reservoir top 62 comprises a cylindrical refractory member 63 fonnedof a suitable material, such as an asbestos-silica composition which issold under the name Marinite. Usually, refractory cylinder 63 is made upof a plurality of Marinite rings bonded together by a suitablerefractory adhesive. Means (not shown) are usually provided to urge thereservoir top 62 into engagement with the mold to prevent molten metalleakage therebetween.

Illustrated in FIG. 6 is a further embodiment of the present inventionwhich is primarily directed to horizontal DC casting. The mold assemblyshown generally comprises a tubular mold body 10 which has a flangeportion 11 at the end of the mold body 10. Associated with the mold body10 is a water jacket 13 comprising a first extended portion 15 which isgenerally concentric with the mold body 10 and a second extended portion16 generally perpendicular to said first portion and generally defininga coolant chamber 14 with baffle member 18. Conduit 23 is providedbetween baffle member 18 and extended portion 15 to direct a stream ofhigh velocity coolant at the junction of the mold body 10 and moldflange 11 so as to effect a high heat transfer rate in that area andthen through conduits 20 and 22 to spray onto the emerging ingot. Theconduit 23 can be a continuous slot or can be series of apertures.Spacing member 19, which is shown as being integral with baffle member18, is provided to positively position the mold body with respect to thebaffle member. An upper surface of member 15 is provided with a grooveor recess 31 which is adapted to receive a resilient, rubber-like O-ring32. Collar 35 is positioned adjacent the extreme face of member 15 andflange I1 and suitably provided with grooves 70 and 71 adapted toreceive resilient, rubber-like O-rings 72 and 7,3. Suitable means, suchas screw member 74, are provided to engage the collar with the moldflange and waterjacket and urge these members into a water-tight sealingengagement. The collar 35 is provided with a shoulder 75 to engage theorifice plate 80. Connecting means 82 are provided to urge the entiremold assembly into, and in particular orifice plate 80, a sealingengagement with plate 83 of the refractory lined molten metal trough 84.Lubricant is introduced through connection 76 in collar 35 and is fed tothe surface of the mold flange 11 through conduit 75. A suitable porousgasket 77 formed of refractory material, such as Fiberfrax, is providedon the upper surface of the mold flange so as to provide a means fortransporting lubricant from the conduit 75 to the innermost surface 12of the mold body. Other means, such as suitable lubrication gaps, canalso be employed.

FIG. 7 is a partial cross-sectional view of the embodiment shown in FIG.I and generally is the same except that the spacing member 19' is formedintegral with the mold body 10 and that the spacing member 19' is seatedinto recess 21' provided in the surface of baffle member 18.

As is evident from the above discussion, the tubular flange molddescribed is relatively simple in design, and thus relativelyinexpensive to make. Essentially all coolant and lubricant conduits arein other members of the mold assembly not the mold body. Because of thesimple mold design which requires relatively little machining, it isfrequently less expensive to discard a used mold and replace it with anew one rather than to try to refurbish a used mold.

Although the above discussion and drawings are directed to circularmolds, the present invention is generally applicable to both square andrectangular molds or molds of any shape. Moreover, it is obvious thatvarious modifications and improvements can be made without departingfrom the spirit of the present invention and the scope of the appendedclaims.

What is claimed is:

l. A DC mold assembly for casting light metals which allows for therapid change of the mold body comprising in combination a. an open-endedtubular mold body provided with a flange extending out radially from thefeed end of the mold body and provided with at least one recess in theouter surface of the mold body;

b. a coolant jacket comprising a first extending leg generallyconcentric with the mold body, a second extending leg generallyperpendicular to the first extending leg and a baffle member disposedbetween the first extending leg and the mold body, the mating surfacesof the first extending leg and the mold flange being adapted to receivea coolantsealing gasket;

c. at least one spacing member extending inwardly from the baffle memberand seated in the recess provided in the outer surface of the mold bodyto thereby positively position radially and axially the mold body withrespect to the baffle member and define a plurality of conduits whichallow the pas sage of coolant from the conduit defined by the bafflemember and the mold body to the surface of an emerging ingot duringcasting;

d. a resilient, rubber-like gasket provided between the mating surfacesof the first extending leg of the coolant jacket and the mold flange;and

e. means to urge the mold flange into a water-tight engagement with thefirst extending leg of the coolant jacket.

2. The mold assembly of claim 1 where said spacing member is aprojecting ridge formed integral with said baffle member and is providedwith a plurality of coolant carrying passageways.

3. The mold assembly of claim 1 comprising a gasket material having adurometer hardness from about 25-80.

4. The mold assembly of claim 1 wherein said gasket material is in theform of an O-ring.

5. The mold assembly of claim 4 wherein the upper surface of verticallyextending leg of said coolant jacket is provided with a recess adaptedto receive said O-ring.

6. The mold assembly of claim 1 wherein said mold flange is urged intowater-tight engagement with said coolant jacket with a force less than500 pounds.

7. The mold assembly of claim 4 wherein said gasket material has adurometer hardness from about 30-60.

8. The mold assembly of claim 1 wherein said urging means includes acollar positioned on the upper surface of said mold flange.

9. The mold assembly of claim 1 wherein said baffle member is a separatemember and is seated and supported in a recess provided in saidhorizontally dis' posed portion of said coolant jacket.

10. The mold assembly of claim 1 provided with sec ond conduit means influid communication with the coolant chamber defined by the mold flange.the first and second extending legs of the coolant jacket and the bafflemember to direct coolant from said chamber onto the outer surface of themold body in the area of the junction of the mold flange and mold bodyso as to maintain a high heat transfer rate in said area 11. A DC moldassembly for castin; light metals comprising in combination a. anopen-ended tubular mold body provided with a flange extending outradially from the feed end of said mold body and provided with at leastone recess in the outer surface thereof;

b. a coolant jacket comprising a first extending leg generallyconcentric with the mold body, a second extending leg generallyperpendicular to the first extending leg and a baffle member disposedbetween the first extending leg and the mold body, the mating surfacesof the first extending leg and the mold flange adapted to receive acoolant sealing gasket;

c. at least one spacing member extending inwardly from said bafflemember and seated in the recess provided in the outer surface of themold body to thereby positively position radially and axially the moldbody with respect to the baffle member and define a plurality ofconduits which allow the passage of coolant from the conduit defined bythe baffle member and the mold body to the surface of an emerging ingotduring casting; and

d. means to urge said mold flange into a water-tight sealing engagementwith said first extending leg of said coolant jacket.

12. The mold assembly of claim 11 wherein said spacing member is aprojecting ridge formed integral with the baffle member and is providedwith a plurality of coolant carrying passageways adapted to directcoolant onto the surface of an emerging ingot during cast- 13. The moldassembly of claim 11 provided with conduit means in fluid communicationwith the coolant chamber defined by the mold flange the first and second extending legs of the coolant jacket and the baffle member to directcoolant from said chamber onto the outer surface of the mold body in thearea of the junction of the mold flange and mold body so as to maintaina high heat transfer rate in said area.

1. A DC mold assembly for casting light metals which allows for therapid change of the mold body comprising in combination a. an open-endedtubular mold body provided with a flange extending out radially from thefeed end of the mold body and provided with at least one recess in theouter surface of the mold body; b. a coolant jacket comprising a firstextending leg generally concentric with the mold body, a secondextending leg generally perpendicular to the first extending leg and abaffle member disposed between the first extending leg and the moldbody, the mating surfaces of the first extending leg and the mold flangebeing adapted to receive a coolant-sealing gasket; c. at least onespacing member extending inwardly from the baffle member and seated inthe recess provided in the outer surface of the mold body to therebypositively position radially and axially the mold body with respect tothe baffle member and define a plurality of conduits which allow thepassage of coolant from the conduit defined by the baffle member and themold body to the surface of an emerging ingot during casting; d. aresilient, rubber-like gasket provided between the mating surfaces ofthe first extending leg of the coolant jacket and the mold flange; ande. means to urge the mold flange into a water-tight engagement with thefirst extending leg of the coolant jacket.
 2. The mold assembly of claim1 where said spacing member is a projecting ridge formed integral withsaid baffle member and is provided with a plurality of coolant carryingpassageways.
 3. The mold assembly of claim 1 comprising a gasketmaterial having a durometer hardness from about 25-80.
 4. The moldassembly of claim 1 wherein said gasket material is in the form of anO-ring.
 5. The mold assembly of claim 4 wherein the upper surface ofvertically extending leg of said coolant jacket is provided with arecess adapted to receive said O-ring.
 6. The mold assembly of claim 1wherein said mold flange is urged into water-tight engagement with saidcoolant jacket with a force less than 500 pounds.
 7. The mold assemblyof claim 4 wherein said gasket material has a durometer hardness fromabout 30-60.
 8. The mold assembly of claim 1 wherein said urging meansincludes a collar positioned on the upper surface of said mold flange.9. The mold assembly of claim 1 wherein said baffle member is a separatemember and is seated and supported in a recess provided in saidhorizontally disposed portion of said coolant jacket.
 10. The moldassembly of claim 1 provided with second conduit means in fluidcommunication with the coolant chamber defined by the mold flange, thefirst and second extending legs of the coolant jacket and the bafflemember to direct coolant from said chamber onto the outer surface of themold body in the area of the junction of the mold flange and mold bodyso as to maintain a high heat transfer rate in said area.
 11. A DC moldassembly for casting light metals comprising in combination a. anopen-ended tubular mold body provided with a flange extending outradially from the feed end of said mold body and provided with at leastone recess in the outer surface thereof; b. a coolant jacket comprisinga first extending leg generally concentric with the mold body, a secondextending leg generally perpendicular to the first extending leg and abaffle member disposed between the first extending leg and the moldbody, the mating surfaces of the first extending leg and the mold flangeadapted to receive a coolant sealing gasket; c. at least one spacingmember extending inwardly from said baffle member and seated in therecess provided in the outer surface of the mold body to therebypositively position radially and axially the mold body with respect tothe baffle member and define a plurality of conduits which allow thepassage of coolant from the conduit defined by the baffle member and themold body to the surface of an emerging ingot during casting; and d.means to urge said mold flange into a water-tight sealing engagementwith said first extending leg of said coolant jacket.
 12. The moldassembly of claim 11 wherein said spacing member is a projecting ridgeformed integral with the baffle member and is provided with a pluralityof coolant carrying passageways adapted to direct coolant onto thesurface of an emerging ingot during casting.
 13. The mold assembly ofclaim 11 provided with conduit means in fluid communication with thecoolant chamber defined by the mold flange, the first and secondextending legs of the coolant jacket and the baffle member to directcoolant from said chamber onto the outer surface of the mold body in thearea of the junction of the mold flange and mold body so as to maintaina high heat transfer rate in said area.